The paper presented a based on Beidou RNSS positioning module as the core, give an ocean hydrological data flow monitoring terminal design using communication of RDSS Beidou, the terminal can follow marine drift on ocean currents, terminal collected hydrological data of the position and sent to the monitoring center and receive center instruction. The terminal uses the high integration, high efficiency, ultra low power ARM processor as well as the timing module, uses the low power design and the optimized power management to extend the use time of the terminal.